1. Field of the Invention
The present invention relates to a viscoelasticity measuring instrument adapted to apply AC stress or strain to a sample, detect the strain or stress occurring in the sample during this time and measure the viscoelasticity of the sample on the basis of the correlation between the stress and strain.
2. Background Information
A conventional instrument (disclosed in, for example, JP-A-11-218483) is known which is adapted to apply AC stress or strain to a sample, detect the strain or stress occurring in the sample during this time and measure a complex elastic modulus of the sample on the basis of the correlation between the stress and strain.
This related art instrument is provided with a structure for displaying an error mark of “non-measurement-executable” when the strain occurring in a sample is too small or too large to normally calculate a viscoelasticity of the sample, and immediately finishing the measurement operation, or a structure for continuing the measurement operation ignoring the error mark of “non-measurement-executable”.
In general, a sample to be measured becomes softer when the temperature thereof becomes higher. Especially, in the case of a resin sample, phenomena, such as glass transition and melting, occur, i.e., the resin is softened at a high temperature. Conversely, in the case of a thermosetting resin, the resin gels and is soft at a low temperature, and becomes hard at a high temperature in some cases due to a hardening reaction. In order to measure the viscoelasticity of an unknown sample, a temperature range in which the hardness of the sample can be measured cannot be determined unless the measuring of the sample is practically done.
Therefore, in a related art instrument, the measurement of an unknown sample is conducted at a temperature in an experimentally estimated range. When the error mark of “non-measurement-executable” is displayed during the measurement, a method of trial and error in which an operator puts detection and measurement operations into practice repeatedly while changing the range of temperature little by little was carried out.
As a result, in order to measure an unknown sample, it is necessary that measurement operations be conducted many times by way of trial until a temperature range in which the measurement of the sample can be conducted, so that much labor and much time were taken.
In the case of the structure in which measurement keeps being conducted with an error mark displayed ignored, wasteful measurement is necessarily carried out in repetition, so that a measuring efficiency is low.
An object of the present invention is to solve these inconveniences, i.e., to reduce the measuring labor and finding out a measurement executable temperature at a high speed and with a high accuracy.